Music Theory Crash Course

Before you start Learn Music Theory, we wanted to give you a quick crash course of the basics. If you can understand the fundamentals of pitch, intervals, scales, and chords, you’ll be set to start exploring the rest of the course. So, let’s jump in.

So...What is a note?

All sound is caused by vibration. What we call a musical note is a sound of a specific and stable pitch, meaning a specific and stable vibration.

How high or how low a note sounds depends on the frequency of the vibrations. The higher the frequency of the vibration, the higher the pitch of the note, and vice versa.

If you double the frequency of a note, you have gone up an octave. This means the note will sound the same, but higher. For example, the note 'A' roughly in the middle of your keyboard will vibrate 440 times a second, the 'A' above it 880 times a second, and the one below it 220 times a second (vibrations per second are measured in 'Hertz', shortened to 'Hz').

Note Names

When you look at a keyboard, you see a repeating pattern of 12 notes. This is because in Western music we divide the octave into 12 equal steps.

Notes are named after the letters of the alphabet, from A to G, back to A again. As I'm sure you've noticed, being as smart and brilliant as you are, that is only seven letters, not twelve. That's because five of the notes have letter names and are also designated sharp or flat. On a piano, all the black keys are sharp or flat. Sharp notes (shown by the symbol ♯) are one note higher than the natural note. So, go up to the nearest black note from C and you are on C sharp. Flat notes (shown with the symbol ♭) are the opposite: go down to the nearest black note from D and you are on D flat. The diagram below shows you how this works.

As you can see, this means there are two different note names for each black key. Notes that have different names but the same pitch, like C sharp and D flat, are referred to as 'enharmonic'.

What makes a scale sound like a scale?

There are 12 notes used in Western music, but your standard major and minor scales use just 7 of those notes.

As you might have guessed, if we are not using all the notes when playing a scale then we are skipping certain notes, meaning some of the distances between notes will be bigger than others (the distance between any two notes is called an interval). To move to the nearest note is to move a semitone, and to go one step further than this (the distance of two semitones) is called a tone.

What makes musical scales sound different from one another is that they have their own patterns of tones and semitones. The major scale, which is the basis for most music we hear, has this pattern of intervals:

T T S T T T S

If you start the pattern on the note C on a keyboard, you end up playing all the white notes.

Whatever note you start playing on, this pattern of intervals will create a major scale, just using a different set of notes. Let's have a look at the G major scale. You'll see that we now have one of the black notes in our major scale, an F sharp.

Intervals

As we saw earlier, the difference in pitch between two notes is called an interval. Before, we were simply dealing with tones and semitones, but these terms don't always cut it I'm afraid. There is a whole system you have to learn using numbers, and it's very important that you do learn it, because it is the key to understanding how chords are built, harmonic relationships, scale construction and much much more. So pay attention!

Intervals are represented by numbers showing the distance between the notes along the scale, preceded by a description as either major, minor, perfect, augmented or diminished, depending on the interval.

In a major scale, the third note of the scale is 4 semitones up from the tonic of the scale. In a minor scale, it is only 3 semitones up from the tonic. That's why the interval of 3 semitones is called a minor 3rd and 4 semitones a major 3rd.

Remember! A minor interval is always one semitone flatter than its major counterpart.

In both minor and major scales the 4th and 5th of the scale remain the same size interval from the tonic. There is no minor 4th, or major 5th, for example. These intervals are called perfect. C to F is a perfect 4th, and C to G is a perfect 5th.

Here is a table detailing all the intervals:

Remember! In this table, all the intervals are shown in relation to the starting point of C. But these intervals can of course be made from any starting point.

The best way to get all of this information in your head is to practise. The quicker you can give the interval between any two notes the better.

What's a triad?

Right, so what exactly is a chord? Simply put, it is several notes all played simultaneously. OK, so what's a triad? It's a chord made of three notes, as the word would suggest.

How To Make A Triad

Triads are typically made out of stacked 3rds. Another way of putting this is to say 'play a note, skip a note, play a note, skip a note, play a note'. Starting on the first note of the scale this means playing the notes on the positions 1 - 3 - 5.

For a nice, clear demonstration of what this means, simply play a C on a piano, play the 3rd above it, the E, and then play the 3rd above that, the G.

This is a major chord, or major triad. This is because the note in the middle, the 3rd, is a major 3rd. If you lower it a semitone to a minor 3rd you get...you guessed it, a minor triad. The 1st and the 5th of the chord are the same, it is only the 3rd that is different.

If you build triads on every position of the major scale, using just the notes in that scale, this is the sequence of chords you create:

Major - Minor - Minor - Major - Major - Minor - Diminished

Ah yes, the diminished triad, I'm sure you noticed it. This is like a minor triad, except the 5th of the chord is flattened by one semitone.

The most commonly used and most important chords in a major key are the ones built on the 1st, 4th and 5th positions of the scale. In C major, these chords are C major, F major and G major.

Have you been paying attention?

We're now going to test you on the things taught during this crash course, so if you need a refresher go back and watch some of the videos and then jump in!